SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f68ed0b706d9457bdd06b390991efb22fe89867f336811a3f12567fa4b17b94' 
  AND token = '1rnsXI3FUt3TCfrxvvLLHqqN/FqNPOMeNydGWCORDG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}